Ecosystems

, 9:501 | Cite as

Patterns of Below- and Aboveground Biomass in Eucalyptus populnea Woodland Communities of Northeast Australia along a Rainfall Gradient

  • Ayalsew Zerihun
  • Kelvin D. Montagu
  • Madonna B. Hoffmann
  • Steven G. Bray
Article

Abstract

In vegetated terrestrial ecosystems, carbon in below- and aboveground biomass (BGB, AGB) often constitutes a significant component of total-ecosystem carbon stock. Because carbon in the BGB is difficult to measure, it is often estimated using BGB to AGB ratios. However, this ratio can change markedly along resource gradients, such as water availability, which can lead to substantial errors in BGB estimates. In this study, BGB and AGB sampling was carried out in Eucalyptus populnea-dominated woodland communities of northeast Australia to examine patterns of BGB to AGB ratio and vertical root distribution at three sites along a rainfall gradient (367, 602, and 1,101 mm). At each site, a vegetation inventory was undertaken on five transects (100 × 4 m), and trees representing the E. populnea vegetation structure were harvested and excavated to measure aboveground and coarse-root (diameter of at least 15 mm) biomass. Biomass of fine and small roots (diameter less than 15 mm) at each site was estimated from 40 cores sampled to 1 m depth. The BGB to AGB ratio of E. populnea-dominated woodland plant communities declined from 0.58 at the xeric end to 0.36 at the mesic end of the rainfall gradient. This was due to a marked decline in AGB with increased aridity whereas the BGB was relatively stable. The vertical distribution of fine roots in the top 1 m of soil varied along the rainfall gradient. The mesic sites had more fine-root biomass (FRB) in the upper soil profile and less at depth than the xeric site. Accordingly, at the xeric site, a much larger proportion of FRB was found at depth compared to the mesic sites. The vertical distribution patterns of small roots of the E. populnea woodland plant communities were consistently )-shaped, with the highest biomass occurring at 15–30-cm depth. The potential significance of such a rooting pattern for grass–tree and shrub–tree co-existence in these ecosystems is discussed. Overall, our results revealed marked changes in BGB to AGB ratio of E. populnea woodland communities along a rainfall gradient. Because E. populnea woodlands cover a large area (96 M ha), their contribution to continental-scale carbon sequestration and greenhouse gas emission can be substantial. Use of the rainfall-zone-specific ratios found in this study, in lieu of a single generic ratio for the entire region, will significantly improve estimates of BGB carbon stocks in these woodlands. In the absence of more specific data, our results will also be relevant in other regions with similar vegetation and rainfall gradients (that is, arid and semiarid woodland ecosystems).

Keywords

Eucalyptus populnea rainfall gradient arid and semiarid woodlands root-to-shoot ratio vertical root distribution pattern vegetation thickening Australia 

Notes

Acknowledgements

We are grateful to P. Back, D. Bell, J. Chandler, J. Compton, Dr. C. Dean, K. Düttmer, B. Fisher, D. Giles, D. Myles, S. Wood and M. Yee for their help in field sampling and/or laboratory sample processing. Dr. Annette Cowie provided useful comments on an early version of the manuscript. We also thank Dr. J. H. Schenk and an anonymous reviewer for comments that helped to improve the manuscript.

References

  1. Back PV, Anderson ER, Burrows WH, Kennedy MJJ, Carter JO. 1997. ‘TRAPS’ transect recording and processing system: woodland monitoring manual. Rockhampton: Queensland Department of Primary Industries. p. 36Google Scholar
  2. Beeston GR, Walker PJ, Purdie R, Pickard J. 1980. Plant communities of the popular box (Eucalyptus populnea) lands of eastern Australia. Aust Rangeland J 2:1–16CrossRefGoogle Scholar
  3. Bloom AJ, Chapin FS III, Mooney HA. 1985. Resource limitation in plants—an economic analogy. Annu Rev Ecol Syst 16:363–92Google Scholar
  4. Burrows WH, Hoffmann MB, Compton JF, Back PV, Tait LJ. 2000. Allometric relationships and community biomass estimates for some dominant eucalypts in Central Queensland woodlands. Aust J Bot 48:707–714CrossRefGoogle Scholar
  5. Burrows WH, Henry BK, Back PV, Hoffmann MB, Tait LJ, Anderson ER, Menke N, others. 2002. Growth and carbon stock change in eucalypt woodlands in northeast Australia: ecological and greenhouse sink implications. Glob Change Biol 8:769–84CrossRefGoogle Scholar
  6. Cairns MA, Brown S, Helmer E, Baumgardner GA. 1997. Root biomass allocation in the world’s upland forests. Oecologia 111:1–11CrossRefGoogle Scholar
  7. Casper BB, Schenk HJ, Jackson RB. 2003. Defining a plant’s belowground zone of influence. Ecology 84:2313–21Google Scholar
  8. Chapin FS III, Autumn K, Pugnaire F. 1993. Evolution of suites of traits in response to environmental stress. Am Nat 142:S78–S92CrossRefGoogle Scholar
  9. Comeau PG, Kimmins JP. 1989. Above- and below-ground biomass and production of ledgepole pine on sites with differing moisture regimes. Canad J For Res 19:447–54Google Scholar
  10. Compton JF, Tait LJ, Hoffmann MB, Myles DJ. 1999. Root–shoot ratios and root distribution for woodland communities across a rainfall gradient in central Queensland. In: Eldridge D, Freudenberger D, Eds. People and rangelands: building the future. Proceedings of the VIth international rangeland Congress. Canberra: Australian Academy of Sciences. p. 924–5Google Scholar
  11. Eamus D, Chen X, Kelley G, Hutley LB. 2002. Root biomass and root fractal analyses of an open Eucalyptus forest in a savanna of north Australia. Aust J Bot 50:31–41CrossRefGoogle Scholar
  12. Friedlingstein P, Joel G, Field CB, Fung IY. 1999. Toward an allocation scheme for global terrestrial carbon models. Glob Change Biol 5:755–70CrossRefGoogle Scholar
  13. Greene RSB, Chartres CJ, Hodgkinson KS. 1990. The effects of fire on the soil in a degraded semi-arid woodland. I. Cryptogam cover and physical and micromorphological properties. Aust J Soil Res 28:755–77CrossRefGoogle Scholar
  14. Harrington GN. 1979. Estimation of above-ground biomass of trees and shrubs in a Eucalyptus populnea F. Muell. woodland by regression of mass on trunk diameter and plant height. Aust J Bot 27:135–43CrossRefGoogle Scholar
  15. Hodgki nson KC. 1992. Water relations and growth of shrubs before and after fire in a semi-arid woodland. Oecologia 90:467–73CrossRefGoogle Scholar
  16. Jeffrey SJ, Carter JO, Moodie KM, Beswick AR. 2001. Using spatial interpolation to construct a comprehensive archive of Australian climate data. Environ Model Softw 16:309–30CrossRefGoogle Scholar
  17. Johns GG. 1984. Soil water storage in a semi-arid Eucalyptus populnea woodland invaded by shrubs, and the effects of shrub clearing and tree ring barking. Austr Rangeland J 6:75–85CrossRefGoogle Scholar
  18. Knoop WT, Walker BH. 1985. Interactions of woody and herbaceous vegetation in a southern African savanna. J Ecol 73:235–53Google Scholar
  19. Lawson GW, Jenik J, Armstrong-Mensah KO. 1968. A study of a vegetation catena in Guinea savanna at Mole game reserve (Ghana). J Ecol 56:505–522Google Scholar
  20. MacFall JS, Johnson GA, Kramer PJ. 1991. Comparative water uptake by roots of different ages in seedlings of loblolly pine (Pinus teada L.). New Phytol 119:551–560CrossRefGoogle Scholar
  21. McPherson GR, Boutton TW, Midwood AJ. 1993. Stable carbon isotope analysis of soil organic matter illustrates vegetation change at the grassland/woodland boundary in southern Arizona, USA. Oecologia 93:95–101Google Scholar
  22. Northcote KH. 1979. A factual key for the recognition of Australian soils. 4th ed. Glenside, (South Australia): Rellim Technical Publications. 123 pGoogle Scholar
  23. Santantonio D, Hermann RK. 1985. Standing crop, production, and turnover of fine roots on dry, moderate, and wet sites of mature Douglas fir in western Oregon. Ann Sci For 42:113–42Google Scholar
  24. Schenk HJ, Jackson RB. 2002a. The global biogeography of roots. Ecol Monogr 72:311–328Google Scholar
  25. Schenk HJ, Jackson RB. 2002b. Rooting depths, lateral root spreads and below-ground/above-ground allometries of plants in water-limited ecosystems. J Ecol 90:480–494CrossRefGoogle Scholar
  26. Scholes RJ, Archer SR. 1997. Tree-grass interactions in savannas. Annual Rev Ecol Syst 28:517–44CrossRefGoogle Scholar
  27. Schulze E-D, Mooney HA, Sala OE, Jobbagy E, Buchmann N, Bauer G, Canadell J, others. 1996. Rooting depth, water availability, and vegetation cover along an aridity gradient in Patagonia. Oecologia 108:503–511CrossRefGoogle Scholar
  28. Schulze E-D, Williams RJ, Farquhar GD, Schulze W, Langridge J, Miller JM, Walker BH. 1998. Carbon and nitrogen isotope discrimination and nitrogen nutrition of trees along a rainfall gradient in northern Australia. Aust J Plant Physiol 25:413–25CrossRefGoogle Scholar
  29. Schuur EAG, Matson PA. 2001. Net primary productivity and nutrient cycling across a mesic to wet precipitation gradient in Hawaiian montane forest. Oecologia 128:431–42CrossRefGoogle Scholar
  30. Steudle E, Peterson CA. 1998. How does water get through roots? J Exp Bot 49:775–88CrossRefGoogle Scholar
  31. van Auken OW. 2000. Shrub invasions of North American semiarid grasslands. Annu Rev Ecol Syst 31:197–215CrossRefGoogle Scholar
  32. Vogt KA, Vogt DJ, Palmiotto PA, Boon P, O’Hara J, Asbjornsen H. 1996. Review of root dynamics in forest systems grouped by climate, climate forest type and species. Plant Soil 187:159–219CrossRefGoogle Scholar
  33. Walter H. 1971. Ecology of tropical and subtropical vegetation. Edinburgh: Oliver & BoydGoogle Scholar
  34. Weston EJ, Thompson DF, Scott BJ. 1980. Current land use in the poplar box (Eucalyptus populnea) lands. Austr Rangeland J 2:31–40CrossRefGoogle Scholar
  35. Williams RJ, Duff GA, Bowman DMJS, Cook GD. 1996. Variation in the composition of tropical savannas as a function of rainfall and soil texture along a large-scale climatic gradient in the Northern Territory, Australia. J Biogeogr 23:747–56Google Scholar
  36. Zerihun A, Montagu KD. 2004. Belowground to aboveground biomass ratio and vertical root distribution responses of mature Pinus radiata D. Don. stands to phosphorus fertilisation at planting. Can J For Res 34:1883–94CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Ayalsew Zerihun
    • 1
    • 2
  • Kelvin D. Montagu
    • 1
    • 2
  • Madonna B. Hoffmann
    • 2
    • 3
  • Steven G. Bray
    • 2
    • 3
  1. 1.Forest Resources ResearchNew South Wales Department of Primary IndustriesBeecroftAustralia
  2. 2.Cooperative Research Centre for Greenhouse AccountingCanberraAustralia
  3. 3.Queensland Department of Primary Industries and FisheriesRockhamptonAustralia

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